Two-dimensional (2D) monolayer cell culture systems have been used for many years in biological research. The most common cell culture platform is the two-dimensional (2D) monolayer cell culture in petri dishes or flasks. Although such 2D in vitro models are less expensive than animal models and are conducive to systematic, and reproducible quantitative studies of cell physiology (e.g., in drug discovery and development), the physiological relevance of the information retrieved from in vitro studies to in vivo system is often questionable. It has now been widely accepted that three-dimensional (3D) cell culture matrix promotes many biological relevant functions not observed in 2D monolayer cell culture. Said another way, 2D cell culture systems do not accurately recapitulate the structure, function, physiology of living tissues in vivo.
U.S. Pat. No. 8,647,861 describes microfluidic “organ-on-chip” devices comprising living cells on membranes in microchannels exposed to culture fluid at a flow rate. In contrast to static 2D culture, microchannels allow the perfusion of cell culture medium throughout the cell culture during in vitro studies and as such offer a more in vivo-like physical environment. In simple tee's, an inlet port allows injection of cell culture medium into a cell-laden microfluidic channel or chamber, thus delivering nutrients and oxygen to cells. An outlet port then permits the exit of remaining medium as well as harmful metabolic by-products.
While such microfluidic devices are an improvement over traditional static tissue culture models, the small size, scale and interface of these devices makes fluid handling difficult. What is needed is a way to control perfusion of these devices in a manner whereby fluid pressure creates a flow rate that applies a desired fluid shear stress to the living cells. Ideally, the solution should provide for a simple user workflow.